I have lots of reservations. Honestly, I don't think NaNo has much place for a piece that a person really wants to work on being a salable manuscript. NaNo is an inspirational tool to kick-start people who don't sit down every day and put their butts in the chair and write. It's a mad dash to a finish line that doesn't even have to be particularly comprehensible. So in the end, that frantic rushing could make it much harder to salvage a solid manuscript out of what you did in an attempt to make the world goal. It doesn't teach good writing habits. It's a fun little gimmick, and I think it should be taken in that spirit, otherwise you might end up pissed off at yourself for not taking the time to really harvest a great story and instead dashing off a good one.
However, all writing is experience, and thus none of it is ever a waste of time. We always need the practice.
I decided I wouldn't mind shoving off the final tinkering with DT (Devil's Tongue) and working on the second in the series, as I've got most of the synopsis hammered out and I'm really eager.
And even moreso, I really want to get my hands into another juicy story. The second one is easy since I have the entire background figured out. I can pretty much sit down and write. Maybe this would help my funk. Work's been bloody awful, and so stressful I haven't been able to truly consider writing (overtime sucks), but it could help kickstart me back into writing mode.
I don't consider this a replacement for good solid writing habits. I'm trying to figure out a way to beat my stressed out brain into giving writing space again. It's been difficult. But if this kicks me out of it, then thank the writing gods.
And if it doesn't, well, I've started book #2, which is what I need to be doing anyways. The nibbles from the publishers didn't get full bites, and I guess I should be glad that my first real novel has elicited such a positive response, but I need to finish the next one if I'm going to make the sale.
Blergh, darn you, sales.
Although my sweetheart is here for two months, and this is during his time here, he really wants me to get back to writing and has been unhappy that I haven't done much of anything since his arrival. But, well... I had to catch up, couldja blame me?!

I'm not even certain I'll push hard towards the word goal, but I will push hard to make a serious dent in draft 1. It'll be a nice change from the endless sentence tinkering.
So I guess what I'm saying here is - I won't be on the forums much at all next month. Heh. Ah well, I doubt many people will notice my absence anywho. :P
But you're right, it is a good way to get out of the funk! Best wishes with your noveling... don't forget to stock up on coffee and snacks.